Dynamic heat exchanger

ABSTRACT

A rotary heat exchanger includes a housing defining an interior space and heat transfer structure in the interior space. The heat transfer structure includes a plurality of concentric discs disposed in spaced relation to define passageways between the discs. The discs are mounted for rotation within the housing. Partition structure divides the interior space into first and second chambers. When heat transfer structure is rotated and first and second fluids are introduced into the associated chambers and between the passageways, with the first fluid having a temperature greater than a temperature of the second fluid, the discs are rapidly heated thereby removing heat from the first fluid and heating the second fluid.

FIELD OF THE INVENTION

The invention relates to fluid heat exchangers and, more particularly,to regenerative heat exchangers that rotate and have two separatedchambers through which respective heat supplying and heat receivingfluids circulate.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,491,171 discloses a regenerative type heat exchangerhaving a cylindrical roller that rotates. Two media flows are separatedby a divider wall. A first media flow supplies heat and the heats thewall of the roller as the media flow passes through the wall. Since theroller is rotating, the second media flow flows through the previousheated wall and becomes heated. Thus, the heat is removed from the firstmedia flow and heat is supplied to the second media flow. The roller iscomprised of pourable or flowable materials in spherical or granularform.

Other conventional regenerators employ a large foam disc impregnatedwith water that rotates between the two media flows. Although thesematerials have high heat capacity, they are not suitable for quicklyaccumulating heat from the first flow medium and then quicklytransferring the heat to the second flow medium.

Thus, there is a need to provide a dynamic heat transfer device thataccumulates quickly from one media flow and that quickly transfers heatto the other media flow.

SUMMARY OF INVENTION

An object of the invention is to fulfill the need referred to above. Inaccordance with the principles of the present invention, this objectiveis achieved by providing a rotary heat exchanger for heat exchangebetween at least two fluids. The rotary heat exchanger includes ahousing defining an interior space. Heat transfer structure is providedin the interior space of the housing. The heat transfer structure is inthe form of a plurality of concentric, plate-shaped discs disposed inspaced relation to define passageways between the discs. The discs aremounted for rotation within the housing. A first inlet is provided inthe housing for introducing a first fluid into the interior space of thehousing, A second inlet is provided in the housing for introducing asecond fluid into the interior space of the housing. Partition structuredivides the interior space into first and second chambers with the firstinlet communicating with the first chamber and the second inletcommunicating with the second chamber. A first outlet is provided in thehousing for removal of the first fluid from the first chamber after heatexchange with the heat transfer structure, and a second outlet isprovided in the housing for removal of the second fluid from the secondchamber after heat exchange with the heat transfer structure. When heattransfer structure is rotated and the first and second fluids areintroduced into their associated chambers and between the passageways,with the first fluid having a temperature greater than a temperature ofthe second fluid, the discs are rapidly heated thereby removing heatfrom the first fluid and heating the second fluid.

In accordance with another aspect of the invention, a rotary heatexchanger is provided for heat exchange between at least two fluids. Therotary heat exchanger includes a housing defining an interior space.Means for transferring heat is provided in the interior space of thehousing. The means for transferring heat includes a plurality of membersdisposed in spaced relation and mounted on a shaft for simultaneousrotation upon rotation of the shaft. A first inlet is provided in thehousing for introducing a first fluid into the interior space of thehousing and a second inlet is provided in the housing for introducing asecond fluid into the interior space of the housing. Means for dividingthe interior space into first and second chambers is provided, with thefirst inlet communicating with the first chamber and the second inletcommunicating with the second chamber. A first outlet is provided in thehousing for removal of the first fluid from the first chamber after heatexchange with the heat transfer structure, and a second outlet isprovided in the housing for removal of the second fluid from the secondchamber after heat exchange with the heat transfer structure. When themembers are rotated and the first and second fluids are introduced intothe associated chambers and spaces between the members, with the firstfluid having a temperature greater than a temperature of the secondfluid, the members are rapidly heated thereby removing heat from thefirst fluid and heating the second fluid.

Other objects, features, functionality and characteristics of thepresent invention, as well as the methods of operation and the functionsof the related elements of the structure, the combination of parts andeconomics of manufacture will become more apparent upon consideration ofthe following detailed description and appended claims with reference tothe accompanying drawings, all of which form a part of thisspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from the following detaileddescription of the preferred embodiments thereof, taken in conjunctionwith the accompanying drawing, in which:

FIG. 1 is top view, partially in section, of a dynamic heat exchangerprovided in accordance with the principles of an embodiment of thepresent invention.

FIG. 2 is a side view of the dynamic heat exchanger of FIG. 1 shown witha portion thereof removed so that discs are visible, and showing acontroller and motor.

FIG. 3 is an enlarged view of a disc of the heat exchanger of FIG. 2.

FIG. 4 is a side view of a spacer disposed between a pair of discs ofthe heat exchanger of FIG. 2, shown with flocking associated with thespacer.

FIG. 5 is a view of the portion encircled at 5 in FIG. 4.

FIG. 6 is a top view of a spacer of the heat exchanger of FIG. 1 shownwith temperature sensors associated therewith.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENT

With reference to FIGS. 1 and 2, a rotary heat exchanger for heatexchange between at least two fluids is shown, generally indicated at10, in accordance with an embodiment of the invention. The rotary heatexchanger 10 includes a housing 12 defining an interior space 14. Heattransfer structure, generally indicated at 15, is provided in theinterior space 14 and in the embodiment is in the form of a plurality ofconcentric, plate-shaped members or discs 16 disposed in spaced relationto define passageways 18 (FIG. 2) between the discs. Each disc 16 ismounted for rotation within the housing. More particularly, withreference to FIG. 2, each disc 16 is coupled with a common shaft 20 thatis rotated by a motor 22. Each disc 16 is coupled at central portionthereof to the shaft 20. The shaft 20 can be part of the motor 22 orcoupled with a shaft of the motor 22. The discs 16 can be a structuremade from a single material having high thermal conductivity (e.g.,copper). However, in the embodiment of FIG. 3, (note that thickness ofthe disc is not to scale) each disc 16 has a base 24 of a material of acertain thermal conductivity, and at least one layer 26 of material onthe base 24 with a thermal conductivity substantially greater than thecertain conductivity of the base 24. In the embodiment, the base 24 ispreferably composed of a polycarbonate plastic (as in a conventionalcompact disc), or other materials having low thermal conductivity suchas ceramic, steel, etc. Opposing surfaces of the base 24 are coveredwith a thin layer 26 of a heat conductive metal such as, for example,silver, copper, or gold. It is desirable to provide the base 24 as thinas a possible yet mechanically sound so that a plurality of discs 16 canbe provided in a compact space. For example, discs 16 with a 5″ diameterand an overall thickness of about 0.05″ can be used. The more discsused, the more surface area is provided for heat transfer.

With reference to FIG. 1, a first inlet 28 is provided in the housing 12for introducing a first fluid F1 into the interior space 14 of thehousing 12. A second inlet 30 is provided in the housing 12 forintroducing a second fluid F2 into the interior space 14 of the housing12. The inlets 28 and 30 are on opposite ends of the housing 12 so thatthe first and second fluids flow in opposite directions and preferablycounter to the rotation of the discs 16. Thus, the exposure of the discsto the fluid flows F1, F2 is maximized and the heat transfer ratebenefits from the temperature gradient profile of the fluids F1, F2 andthe discs 16. In the embodiment, the fluids F1 and F2 are air, but canbe other fluids.

In the embodiment, the first fluid F1 is at a temperature of about 140°F. and the second fluid F2 is at a temperature of about 40° F. Ofcourse, other fluid temperatures can be uses so long as there is atemperature difference between the fluids F1, and F2. Partitionstructure 32 divides the interior space 14 into first and secondchambers 34, 36, with the first inlet 28 communicating with the firstchamber 24 and the second inlet 30 communicating with the second chamber36. In the embodiment, the partition structure 32 comprises a pluralityof spacers 37 disposed about the shaft 20 and fixed to the housing 12 tomaintain spacing between adjacent discs 16 and to divide the interiorspace 14 into the first and second chambers, 34, 36. Spacers 37′ canalso be associated with the housing 12 near the periphery of the discs16. The rotating discs 16 pass the spacers 37, 37′ with very littleclearance so that fluids F1, F2 passing through the chambers 34, 36 willhave very little exchange.

A first outlet 38 is provided in the housing 12 for removal of the firstfluid F1 from the first chamber 34 after heat exchange with the heattransfer structure 15. A second outlet 40 is provided in the housing forremoval of the second fluid F2 from the second chamber 36 after heatexchange with the heat transfer structure 15.

Thus, when the heat transfer structure 15 is rotated in direction A andthe first and second fluids F1, F2 are introduced into the interiorspace 14 and passageways 18, layers 26 of material on the discs 16 arerapidly heated thereby removing heat from the first fluid F1 and heatingthe second fluid F2. Hence, for example, the second fluid F2 exits theoutlet 36 at a temperature of about 130° F. and the first fluid F1 exitsthe outlet 38 at a temperature of about 45° F.

The rate that heat can be picked up from the flow of fluid F1 anddelivered to the other flow of fluid F2 is increased due to theprovision of the thin-film coating or layers 26 on the discs 16. Thususe of the layers 26 permits higher disc RPM and high heat transfer in asmall package.

The heat transfer can be further enhanced by inducing turbulence to theflow of fluids F1, F2 to disrupt the formation of boundary layers. Thisis particularly advantageous if the fluid is air. The roughness andspacing of the discs 16 can be adjusted to ensure air turbulence.Roughness could be achieved, for example, by providing concentric ridges42 and grooves 44 (FIG. 3) in the layers 26 of the discs 16. Inaddition, employing soft, compliant spacers 37 that separate the discs16 and air flow chambers 34, 36, the ridges have very little effect onair leakage. If fluid leakage past the spacers 37 is an issue, as shownin FIGS. 4 and 5, flocking 39 or flaps, as seal structure, can beassociated with at least portions of the spacers 37 to contact therotating discs 16 to reduce the fluid leakage, without requiring tighttolerances. Flocking 39 or other seal structures can also be provided onspacers 37′.

Since the high thermal conductive surface (layer 26) is on a lowconductive base 24, the heat exchange rate is enhanced. In addition, thespeed of rotation of the discs 16 could be automatically adjusted tomaximize heat exchange. For example, with reference FIG. 6, at least onesensor 46 is mounted to the housing 12 or spacer 37 sing 12 in theinternal space 14 to determine the rate of heat transfer of the heatexchanger 10. The sensor 46 can be a thermistor or other sensor thatsenses temperature or a change in temperature. In the embodiment, foursensors 46 are provided. A signal 49 from the sensor(s) 46 is receivedby a controller 48, preferably having a processor 50. The controller 48monitors the rate of heat transfer by monitoring the temperature signalsover time. If it is determined that the rate of heat transfer needs tobe adjusted, the controller 48 controls the speed of the motor 22accordingly.

Since total separation of the fluids F1 and F2 need not be 100%, therotary heat exchanger 10 can be small, compact, simple and veryefficient.

The heat exchanger can be used to provide fresh air to a house withlittle heat loss, to ventilate a crawl space or basement to removemoisture or Radon gas, to salvage heat from a clothes dryer, to heat orcool air for breathing by a human, etc.

The foregoing preferred embodiments have been shown and described forthe purposes of illustrating the structural and functional principles ofthe present invention, as well as illustrating the methods of employingthe preferred embodiments and are subject to change without departingfrom such principles. Therefore, this invention includes allmodifications encompassed within the spirit of the following claims.

1. A rotary heat exchanger for heat exchange between at least twofluids, the rotary heat exchanger comprising: a housing defining aninterior space, heat transfer structure in the interior space of thehousing, the heat transfer structure being in the form of a plurality ofconcentric, plate-shaped discs disposed in spaced relation to definepassageways between the discs, the discs being mounted for rotationwithin the housing, a first inlet in the housing for introducing a firstfluid into the interior space of the housing, a second inlet in thehousing for introducing a second fluid into the interior space of thehousing, partition structure dividing the interior space into first andsecond chambers with the first inlet communicating with the firstchamber and the second inlet communicating with the second chamber, afirst outlet in the housing for removal of the first fluid from thefirst chamber after heat exchange with the heat transfer structure, anda second outlet in the housing for removal of the second fluid from thesecond chamber after heat exchange with the heat transfer structure,wherein when the heat transfer structure is rotated and the first andsecond fluids are introduced into their associated chambers and betweenthe passageways, with the first fluid having a temperature greater thana temperature of the second fluid, the discs are rapidly heated therebyremoving heat from the first fluid and heating the second fluid.
 2. Therotary heat exchanger of claim 1, wherein each disc has a base with amaterial of a certain thermal conductivity, and at least a layer ofmaterial on the base with a thermal conductivity substantially greaterthan the certain conductivity.
 3. The rotary heat exchanger of claim 1,wherein the partition structure comprises a plurality of spacers thatspace the discs a distance apart.
 4. The rotary heat exchanger of claim2, wherein the base is of composed of polycarbonate plastic and thelayer of material on the base is a metal.
 5. The rotary heat exchangerof claim 2, wherein the base is of composed of plastic material and thelayer of material on the base is a metal.
 6. The rotary heat exchangerof claim 5, wherein the metal is one of silver, copper or gold.
 7. Therotary heat exchanger of claim 5, wherein the metal is one of silver,copper or gold.
 8. The rotary heat exchanger of claim 2, wherein eachbase has opposing surfaces and said layer of material is on eachopposing surface.
 9. The rotary heat exchanger of claim 1, wherein thefirst and second inlets are at opposite ends of the housing so that thefirst and second fluids can flow in opposite directions and counter tothe rotation of the discs.
 10. The rotary heat exchanger of claim 2,wherein the layer of material has a plurality of ridges and groovestherein to promote turbulent flow of the fluids over the discs.
 11. Therotary heat exchanger of claim 1, wherein each disc is coupled with acommon shaft for rotation therewith.
 12. The rotary heat exchanger ofclaim 3, further including seal structure associated with the spacers soas to provide a seal with respect to the discs.
 13. The rotary heatexchanger of claim 1, in combination with a motor, a controller and atleast one sensor, the motor being constructed and arranged to rotate theheat transfer structure, the sensor being constructed and arranged tosense temperature changes within the heat exchanger, the sensor beingconstructed and arranged to send a signal to the controller such thatthe controller can control the speed of the motor to control a heattransfer rate of the heat exchanger.
 14. A rotary heat exchanger forheat exchange between at least two fluids, the rotary heat exchangercomprising: a housing defining an interior space, means for transferringheat in the interior space of the housing, the means for transferringheat including a plurality of members disposed in spaced relation andmounted on a shaft for simultaneous rotation upon rotation of the shaft,a first inlet in the housing for introducing a first fluid into theinterior space of the housing, a second inlet in the housing forintroducing a second fluid into the interior space of the housing, meansfor dividing the interior space into first and second chambers with thefirst inlet communicating with the first chamber and the second inletcommunicating with the second chamber, a first outlet in the housing forremoval of the first fluid from the first chamber after heat exchangewith the heat transfer structure, and a second outlet in the housing forremoval of the second fluid from the second chamber after heat exchangewith the heat transfer structure, wherein when the members are rotatedand the first and second fluids are introduced into the associatedchambers and spaces between the members, with the first fluid having atemperature greater than a temperature of the second fluid, the membersare rapidly heated thereby removing heat from the first fluid andheating the second fluid.
 15. The rotary heat exchanger of claim 14,wherein each member has a base with a material of a certain thermalconductivity, and at least a layer of material on the base with athermal conductivity substantially greater than the certainconductivity.
 16. The rotary heat exchanger of claim 14, wherein themeans for dividing comprises a plurality of spacers that space themembers a distance apart.
 17. The rotary heat exchanger of claim 15,wherein the layer of material on the base is a metal.
 18. The rotaryheat exchanger of claim 17, wherein the metal is one of silver, copperor gold.
 19. The rotary heat exchanger of claim 15, wherein each base isa disc having opposing surfaces and said layer of material is on eachopposing surface.
 20. The rotary heat exchanger of claim 14, wherein thefirst and second inlets are at opposite ends of the housing so that thefirst and second fluids can flow in opposite directions and counter tothe rotation of the members.
 21. The rotary heat exchanger of claim 15,wherein the layer of material has a plurality of ridges and groovestherein to promote turbulent flow of the fluids over the members. 22.The rotary heat exchanger of claim 14, wherein each member is coupledwith a common shaft for rotation therewith.
 23. The rotary heatexchanger of claim 16, further including seal structure associated withthe spacers so as to provide a seal with respect to the members.
 24. Therotary heat exchanger of claim 14, in combination with a motor, acontroller and at least one sensor, the motor being constructed andarranged to rotate the means for transferring heat, the sensor beingconstructed and arranged to sense temperature changes within the heatexchanger, the sensor being constructed and arranged to send a signal tothe controller such that the controller can control the speed of themotor to control a heat transfer rate of the heat exchanger.